The thymus is a lobular gland located under the breastbone near the thyroid gland that plays a role in immune function. With age, the thymus is replaced by fat and connective tissue.

According to legend, glandular or organotherapy, which refers to the use of animal tissues or cell preparations to improve physiologic functioning and support the natural healing process, first gained popularity in the early to mid 1900s. The idea of homeopathic glandular therapy was first introduced almost 200 years ago. Thymus extracts for nutritional supplements usually come from young calves (bovine). Bovine thymus extracts are found in capsules and tablets as dietary supplements.

Thymus extract is commonly used to stimulate the immune system and to treat bone marrow failure, autoimmune disorders, chronic skin diseases, recurrent viral and bacterial infections, hepatitis, allergies, chemotherapy side effects, and cancer. Most basic and clinical research involving oral and injectable thymus extract has been conducted in Europe.

Studies in humans suggest promising results in terms of allergies, asthma, cancer, chemotherapeutic side effects, cardiomyopathy (weakening of the heart muscle), chronic obstructive pulmonary disease, HIV/AIDS, liver disease, respiratory tract infections, systemic lupus erythematosus, and tuberculosis and to stimulate the immune system However, not all study results agree, and more well designed studies are still needed in many fields.

These uses have been tested in humans or animals. Safety and effectiveness have not always been proven. Some of these conditions are potentially serious, and should be evaluated by a qualified healthcare provider.

GRADE *

Preliminary evidence suggests that thymus extract may be useful for allergy symptom reduction. More studies are needed before a conclusion can be made involving thymus extract for this use.

C

Preliminary evidence suggests that thymus extract may be useful for hair re-growth. More studies are needed before a conclusion can be made involving thymus extract for this use.

C

Thymus extract has been investigated for use in immune-modulating acute stress and adaptive disorders. More studies are needed before a conclusion can be made involving thymus extract for this use.

C

From the available evidence, any potential benefit of thymus extract is unclear. More studies are needed before a conclusion can be made involving thymus extract for this use.

C

Preliminary evidence suggests that thymus extract may be useful for asthma symptom reduction. More studies are needed before a conclusion can be made involving thymus extract for this use.

C

Thymus extract may be useful for reducing infections, septicemia, and mortality. However, the evidence is mixed. More studies are needed before a conclusion can be made involving thymus extract for this use.

C

Preliminary evidence suggests that thymus extract may reduce side effects of chemotherapy and radiotherapy and increase disease-free survival. Early studies have investigated thymus extract for the treatment of hematopoietic cancer, histiocytosis X, larynx and oropharnygeal cancer, and skin cancer, among others. Additional study is needed in this area.

C

Preliminary evidence suggests that thymus extract may increase left ventricular function, exercise tolerance, and survival. Additional study is needed in this area.

C

Preliminary evidence suggests that thymus extract may be useful for reducing disease exacerbations and hospital admission. More studies are needed before a conclusion can be made involving thymus extract for this use.

C

Thymus extract is of interest for treatment of dermatomyositis (inflammation of the muscles) due to its role in stimulating the immune system. Additional study is needed in this area.

C

Preliminary evidence in conventionally treated patients with type I diabetes suggests that a combination of azathioprine and thymostimulin increased remission. Thymostimulin alone had no effect. Additional study is needed in this area.

C

Preliminary evidence suggests that thymus extract has no clinical effect in patients with subacute sclerosing panencephalitis. However, additional study is needed in this area.

C

More studies are needed before a conclusion can be made involving thymus extract for the treatment of glaucoma or keratitis.

C

Preliminary evidence suggests that thymus extract speeds healing of gastric lesions. More studies are needed before a conclusion can be made involving thymus extract for this use.

C

Preliminary evidence found no improvement in HIV progression to AIDS or immunostimulation, although some immunological activity was noted in a non-randomized controlled trial. Additional study is needed in this area.

C

Thymus extract is of interest in the treatment of human papillomavirus due to its role in immunostimulation. Preliminary positive results were found in five cases. Additional study is needed in this area.

C

Preliminary evidence suggests that thymus extract increases T- and B-lymphocyte counts, the number of rosette-forming cells, and response of T-lymphocytes. Also, in cancer patients, T-activin significantly increases the number of natural killer cells (CD16+). Additional study is needed in this area.

C

Preliminary evidence suggests that thymus extract may offer benefit to individuals with HIV/AIDS and human papillomavirus. Also, thymus extract is of interest due to its role in immunostimulation. More well-designed studies are required in the area of non-hepatitis B and hepatitis B liver disorders before conclusions can be made involving thymus extract for this use.

C

Thymus extract is of interest in the treatment of myelodysplastic syndrome due to its role in immunostimulation in vitro and in human and animal studies. Additional study is needed in this area.

C

Preliminary evidence suggests that both intramuscular and oral thymus extract may be useful for reducing the presence of respiratory tract symptoms. Additional study is need in this area.

C

Despite use of thymus extracts for dermatological conditions, there is currently inconclusive evidence recommending thymus extract for or against the use in skin conditions such as psoriasis or eczema.

C

Preliminary results indicate that articular and cutaneous symptoms associated with systemic lupus erythematosus can be improved with thymus extract use. More studies are needed before a conclusion can be made involving thymus extract for this use.

C

Although inconclusive, preliminary evidence suggests that thymus extract may improve effectiveness of antibacterial therapy in patients with tuberculosis. More studies are needed before a conclusion can be made involving thymus extract for this use.

C

Preliminary evidence from a controlled trial suggests that thymus extract reduces re-infection frequency and infection persistence. More studies are needed before a conclusion can be made involving thymus extract for this use.

C

* Key to grades

A: Strong scientific evidence for this useB: Good scientific evidence for this useC: Unclear scientific evidence for this useD: Fair scientific evidence for this use (it may not work)F: Strong scientific evidence against this use (it likley does not work)

Tradition / Theory
The below uses are based on tradition, scientific theories, or limited research. They often have not been thoroughly tested in humans, and safety and effectiveness have not always been proven. Some of these conditions are potentially serious, and should be evaluated by a qualified healthcare provider. There may be other proposed uses that are not listed below.

There is no proven effective dose for thymus extract. Thymus extract is typically given as an injection, although thymomodulin 80 milligrams has been taken by mouth daily for up to 90 days for the treatment of asthma, and hepatitis B and C. Injections have been given for the treatment of arthritis, breast cancer, burns, cancer, cardiomyopathy, chronic obstructive pulmonary disease, eczema, hepatitis, HIV/AIDS, human papillomavirus infections, immunostimulation, keratitis, liver disease, male infertility, psoriasis, sinusitis, systemic lupus erythematosus, and urinary tract infections. A number of doses have been used, but none have been standardized. Injections should only be given under the supervision of qualified healthcare professionals, including a pharmacist.

Children (younger than 18 years)

There is no proven effective dose for thymus extract in children. A thymus extract has been taken by mouth for three months for the treatment of bronchial asthma. Injections have also been given for recurrent respiratory infections. For example, a dose of thymostimulin 1.5-3 milligrams per kilogram has been injected into the muscle daily for up to 30 days. Injections should only be given under the supervision of qualified healthcare professionals, including a pharmacist.

Safety
The U.S. Food and Drug Administration does not strictly regulate herbs and supplements. There is no guarantee of strength, purity or safety of products, and effects may vary. You should always read product labels. If you have a medical condition, or are taking other drugs, herbs, or supplements, you should speak with a qualified healthcare provider before starting a new therapy. Consult a healthcare provider immediately if you experience side effects.

Allergies

Avoid in individuals with a known allergy or hypersensitivity to thymus extracts. A severe anaphylactic reaction to injected thymostimulin has been documented in a case report. Allergy to thymic extracts has not been demonstrated in currently available clinical trials

Side Effects and Warnings

Use bovine thymus extract supplements cautiously due to potential for exposure to the virus that causes "mad cow disease."

Use of thymus extract is not recommended in patients with myasthenia gravis, untreated hypothyroidism, or thymic tumors due to inadequate available safety information.

Avoid use in patients on hormonal therapy due to preliminary evidence suggesting thymus extract may alter the levels of certain hormones. Also, avoid in patients with a known allergy to thymus or who are pregnant or breastfeeding.

Pregnancy and Breastfeeding

Thymic extract increases human sperm motility and progression. Avoid use during pregnancy or breastfeeding due to inadequate available safety information.

In humans, a combination of azathioprine and thymostimulin may be beneficial in the management of type I diabetes. Caution is advised in patients with diabetes or hypoglycemia, and in those taking drugs, herbs, or supplements that affect blood sugar. Blood glucose levels may need to be monitored by a qualified healthcare professional, including a pharmacist, and medication adjustments may be necessary.

Thymus extract may increase the amount of drowsiness caused by some drugs. Examples include benzodiazepines such as lorazepam (Ativan®) or diazepam (Valium®), barbiturates such as phenobarbital, narcotics such as codeine, some antidepressants, and alcohol. Caution is advised while driving or operating machinery.

Although not well studied in humans, purified thymus gland extract may decrease average thyroid gland weights and serum T3 serum levels and significantly decreased serum T4 levels. It is not clear what effects thymus gland extract would have on external thyroid hormones.

In humans, a combination of azathioprine and thymostimulin may be beneficial in the management of type I diabetes. Caution is advised when using herbs or supplements that may alter blood sugar. Blood glucose levels may require monitoring, and doses may need adjustment.

In humans, thymomodulin had an additive effect on 'conventional medications' for cardiomyopathy. Thymomodulin may also have additive effects on herbal agents that act in a similar manner.

Thymus extract may increase the amount of drowsiness caused by some herbs or supplements. Caution is advised while driving or operating machinery.

Although not well studied in humans, purified thymus gland extract may nonsignificantly decrease average thyroid gland weights and serum T3 levels and significantly decrease serum T4 levels. It is not clear what effects thymus gland extract would have on external thyroid hormone-like herbs or supplements.

The information in this monograph is intended for informational purposes only, and is meant to help users better understand health concerns. Information is based on review of scientific research data, historical practice patterns, and clinical experience. This information should not be interpreted as specific medical advice. Users should consult with a qualified healthcare provider for specific questions regarding therapies, diagnosis and/or health conditions, prior to making therapeutic decisions.